R3303-HP HSR6800 Routers Layer 2 - LAN Switching Configuration Guide

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Performing mCheck globally
Step Command
1. Enter system view.
system-view
2. Perform mCheck.
stp mcheck
Performing mCheck in interface view
Step Command
1. Enter system view.
system-view
2. Enter Ethernet interface view or Layer
2 aggregate interface view.
interface interface-type interface-number
3. Perform mCheck.
stp mcheck
Configuring digest snooping
As defined in IEEE 802.1s, connected devices are in the same region only when their MST region-related
configurations (region name, revision level, and VLAN-to-instance mappings) are identical. A spanning
tree device identifies devices in the same MST region by determining the configuration ID in BPDU
packets. The configuration ID includes the region name, revision level, and configuration digest, which is
in 16-byte length and is the result calculated by using the HMAC-MD5 algorithm based on
VLAN-to-instance mappings.
Because spanning tree implementations vary with vendors, the configuration digests calculated by using
private keys are different. Devices of different vendors in the same MST region cannot communicate with
each other.
To enable communication between an HP device and a third-party device, enable the digest snooping
feature on the port that connects the HP device to the third-party device in the same MST region.
Configuration prerequisites
Before you enable digest snooping, make sure that associated devices of different vendors are connected
and running spanning tree protocols.
Configuration restrictions and guidelines
• With the digest snooping feature enabled, in-the-same-region verification does not need
comparison of configuration digest, so the VLAN-to-instance mappings must be the same on
associated ports.
• When digest snooping is globally enabled, if you modify the VLAN-to-instance mapping or use the
undo stp region-configuration command to restore the default MST region configuration, traffic